About 5 million dental implant procedures were carried out in Europe in 2012. Approximately 18% of these procedures were performed with the use of treatment planning software and approximately 4% of these procedures used mechanical drilling templates as tool for guided surgery.
The use of such drilling templates is still limited because the production thereof is complex, time-consuming (about 3 to 10 days) and expensive (about 300 to 700 FUR per template). Moreover, the overall precision with drilling templates is limited to approximately 1 to 2 mm and the ergonomic situation for the surgeon is not satisfactory, due to the problem of a blocked view during surgery.
EP 2 236 104 B1 discloses a method and a device for medical navigation in which the positional relationship of an instrument with respect to a part of a patient's body is ascertained.
The device comprises an image output on which the instrument and the part of the patient's body are displayed in the correct positional relationship, and an image processor which generates a display of the part of the patient's body on the basis of virtual image data captured by means of a medical imaging method and on the basis of actual images captured during navigation. The device further comprises an image display control which displays the virtual image data on the image output primarily and as the basis of the image, wherein the actual images are superimposed on the virtual image data merely as an addition and secondarily.
The actual images are provided by a video image capture unit which is fixedly arranged on the instrument. The positional relationship of the instrument with respect to the part of the patient's body is ascertained by a stationary tracking system having two cameras and two reference assemblies, one assembly being placed on the part of the patient's body and the other assembly being placed on the instrument. In order to detect this positional relationship at any time during surgery, the two reference assemblies always have to be within the field of vision of the tracking system.
However, the use of the tracking system and the two reference assemblies renders the above device complex. Further, the requirement of the two reference assemblies constantly being located within the field of vision of the stationary tracking system imposes limitations on the applicability of the device. Specifically, in dental and cranio-maxillofacial surgery, in particular, in intraoral applications, in which the area to be treated is arranged within the patient's oral cavity, this requirement may be difficult or even impossible to fulfil, at least throughout the entire surgical procedure.
Hence, there remains a need for a navigation system and a navigation method for dental and cranio-maxillofacial surgery which enable precise surgical navigation in a simple and reliable manner.